Combined lip and shoulder seal for threaded cap

ABSTRACT

An improved cap is provided for sealing an opening formed in an associated bottle. The cap is preferably internally threaded for receipt over a threaded portion of the bottle. A flap extends from a planar surface of the cap and is directed for receipt in the associated bottle opening. A shoulder also extends outwardly from the planar surface and is spaced inwardly from the flap to engage the seal flap as the cap is threaded onto the bottle. The cap is preferably formed of a rigid plastic such as high density polyethylene (HDPE).

BACKGROUND OF THE DISCLOSURE

Blow molded containers or bottles are used for a wide variety of fluidproducts, and find particular use in the dairy industry for milk,juices, flavored waters, etc. The bottle typically includes a raisedshoulder or neck surrounding an opening that is used for introducing orfilling the fluid into the bottle, and likewise the same opening isoftentimes subsequently used for dispensing the fluid from the bottle.In some instances, the opening may be used for only one of filling ordispensing and, in either situation, a closure cap is typicallypositioned over the opening once the bottle has been filled.

Oftentimes, the cap is internally threaded and cooperates with externalthreads on the neck that surround the bottle opening (see, for example,WO2008/091936 developed by the same inventors, the details of which areexpressly incorporated herein by reference). It is desirable for theopening to be sealed from the external environment. This can beaccomplished in a number of different ways. For example, a foil orgasket seal is commonly placed over the opening and secured to thebottle. Although this arrangement provides an effective seal, andprovides a clear indication of whether the seal has been tampered with,the foil seal represents extra material, i.e., the gasket or foil, aswell as additional processing which includes associated equipment,material, and additional time in the processing line to secure thegasket/foil seal over the opening for use in conjunction with the cap.

In other instances, the opening is sealed in a different manner. Forexample, an internal surface of the cap includes a series of closelyspaced concentric ribs, i.e., a series of concentric projectingsurfaces, placed under axial compression as the ribs are essentiallycompressed or crushed against an outer radial surface of the neck as aresult of imposing a high torque on the cap as the cap is threaded ontothe bottle. Because the ribs are compressed, the material used ispreferably a softer material that is capable of being compressed, forexample a polypropylene is commonly used. This arrangement does notprovide a tamper evident feature. Further, if the threads are not wellformed, the torque developed between the neck and cap may beinsufficient to develop the desired force to compress the ribs andprovide an effective seal. Similarly, an imperfect neck finish (e.g., aburr or flash remaining on the neck) will prevent the ribs from beingproperly compressed. As a result, the cap does not properly seal to thebottle.

An alternative manner of sealing the bottle is to use a flexible flapthat extends from the internal surface of the cap and forms aninterference seal with a shoulder on the bottle neck. The flap extendsdownwardly from the inner surface of the cap, and has an outer radialdimension greater than an inner diameter of the bottle opening. Thecross-sectional thickness of the flap preferably decreases as the flapextends outwardly from the cap. Moreover, a distal end of the flap ispositioned for receipt within the neck that forms the opening of thebottle and advantageously centers or orients the cap in place on theneck. Again, a softer material such as a polypropylene is commonly usedfor a cap of this type in order to provide sufficient flexibility to theflap as the flap is urged into sealing engagement with the inner wallsurface of the shoulder that forms the opening. This seal arrangementalso requires a precise fit or else the flap is not properly orientedrelative to the neck and there is no other structure in the arrangementthat holds or guides the flap into the correct location. Further, thisseal arrangement does not provide tamper evidence.

It is still desirable to locate the seal at the edge of the opening, orpreferably inside the throat of the opening. However, this is difficultto do with existing cap designs.

SUMMARY OF THE DISCLOSURE

An improved cap is provided that provides an effective seal with thebottle opening, and substantially decreases the cost per cap.

The cap includes a generally planar surface that overlies the bottleopening. A sidewall extends from the planar surface and surrounds thebottle opening. The lip extends from the planar surface and is directedinwardly from the side wall for receipt in the bottle opening. Ashoulder extends outwardly from the planar surface and is spacedlaterally or radially inwardly from the lip for engaging the seal lip.

Preferably, the lip has a variable thickness along the length thereof.

The cap is preferably formed of a rigid plastic such as HDPE. Theshoulder extends outwardly from the generally planar surface a dimensionless than the lip extends outwardly from the same surface.

In addition, a stop surface may be provided on the cap to operativelyengage a corresponding stop shoulder on the bottle to limit or define amaximum force imposed on the lip and shoulder.

A pour opening may be incorporated into the generally planar member, anda closure lid hinged to the cap.

The pour opening includes a thin-walled tamper-evident member that isintegrally molded with the generally planar member.

A primary advantage associated with the present disclosure is theimproved sealing associated with the new cap.

Another advantage residing in this disclosure relates to thesubstantially reduced costs to manufacture.

Still another benefit is associated with the reduced quality required ofthe neck finish.

Yet another advantage resides in the elimination of components (such asa separate gasket or foil seal) as well as reduced processing time inthe manufacture of the bottle.

Yet another advantage is associated with the ability to provide atamper-evident feature without additional costs.

Still other benefits and advantages of the disclosure will becomeapparent from reading and understanding the following detaileddescription.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a portion of a bottle neck andassociated cap of a prior art arrangement.

FIG. 2 is a cross-sectional view of a portion of a cap of yet anotherprior art arrangement.

FIG. 3 is a perspective view of the new cap with a hinged lid shown inan open position.

FIG. 4 is a plan view of an outer surface of the cap of FIG. 3.

FIG. 5 is cross-sectional view through the new cap taken generally alongthe lines 5-5 of FIG. 4.

FIG. 6 is an enlarged sectional view of the encircled region of FIG. 5.

FIG. 7 is an enlarged view similar to FIG. 6 but illustrating the capsecured to the bottle.

FIGS. 8-10 illustrate plan, elevational, and cross-sectional views of atear away panel that may be included in the cap.

DETAILED DESCRIPTION

FIG. 1 is an enlarged, cross-sectional view of a portion of a capreceived on the neck of a known bottle 100. Particularly, the bottle orcontainer 100 is preferably a thin-walled blow molded plastic bottle asis conventionally used in the dairy industry. The bottle has aweight-to-volume ratio on the order of sixty to seventy grams per gallonand an average wall thickness on the order of 0.010-0.015 millimeters,although the weight-to-volume ratio may be different without departingfrom the scope and intent of the present disclosure. As noted in theBackground, the bottle includes an opening 102 formed by a neck or wall104 that oftentimes protrudes outwardly from a surface 106 of thebottle. The neck typically includes a thread portion such as helicallyextending thread portions 108 that extend at least partially about acircumference or outer surface 110 of wall 104 of the neck. An innersurface 120 of wall 104 defines the opening 102 through the bottle. Theopening is advantageously used to fill the fluid contents into thebottle, and is oftentimes used to also serve as the pour opening forselectively dispensing the fluid contents from the bottle.

In the arrangement shown in FIG. 1, the inner surface 120 forms a sharpcorner or edge 122 with an upper surface 124 of the wall 104. Thesharply defined edge 122 is dimensioned for engagement with flap 140that extends outwardly from cap 142, particularly the planar portion 144thereof. The flap typically depends from an underside surface of theplanar portion 144 at a region spaced radially inward from sidewall 146of the cap. The sidewall likewise includes a thread portion 148 such asthe internal thread portions that cooperate with the external threadportion 108 of the neck. As the cap is threaded onto the bottle, theflap 140, and particularly surface 150 thereof, engages the sharp edge122 of the shoulder. Further axial advancement of the cap onto theshoulder by rotating the cap onto the bottle results in furtherdeflection of the lip 140 and sealing engagement with the edge 122 andinterior surface of the neck.

This interference fit between the flap of the cap with the interiorshoulder of the neck encounters the following problems—it is not alwaysa perfect fit and potential leaking can develop at the cap, there is notamper evidence, and instead requires the additional expense of anadditional foil seal.

An alternative arrangement is shown in FIG. 2. For purposes of brevityand ease of understanding, like reference numerals will refer to likecomponents, while new reference numerals will identify new components.The flap is eliminated in this embodiment, and instead a gasket orseries of ribs 170 extend axially inward from the inner face of planarmember 144, at a location spaced radially inward from the sidewall 146of the cap. Again, the cap is preferably internally threaded asrepresented by reference numeral 148, and the shoulder/wall 104 ispreferably externally threaded as represented by thread portions 108.Upon axial advancement of the cap relative to the shoulder, throughselective rotation of the cap relative to the bottle, the upper surface124 of the shoulder engages the ribs 170. The ribs are compressed orcrushed in order to effect a seal between the cap and the bottle.However, like the embodiment of FIG. 1, there are drawbacks to thisarrangement also (no tamper evidence, imperfect neck finish where a burrwould preclude effective sealing, imperfect threads do not generatedesired sealing force, etc.).

Turning to FIGS. 3-7, the present disclosure relates to a new sealarrangement for a cap used on a bottle. Again, for ease of understandingand brevity, like reference numerals will refer to like components wherepossible, while new elements will be identified by new referencenumerals. More particularly, cap 190 is formed entirely of a highdensity polyethylene, a preferred material of construction. Even usingthis harder material, the cap is able to effectively seal along aninside region of the neck of the bottle opening. Cap 190 includes aplanar portion 192 and sidewall 194 that is disposed substantiallyperpendicular to the planar portion. The sidewall is preferablyinternally threaded as represented by threaded region 196 (such as ahelical thread) that cooperates with external threaded portion 108 ofthe shoulder/wall 102 in much the same manner as described above withrespect to the prior art arrangements. Here, however, a seal flap 200(sometimes referred to as a flapper valve) extends downwardly from thecap, preferably from the interior face of planar region 192, at a regionspaced radially inward from the interior surface of the cap sidewall194. The flap 200 has a tapering conformation in the preferredarrangement that decreases in thickness as it extends away from theplanar portion 192 to an outer terminal end 202. This taperingconformation provides greater flexibility to the flap adjacent its outerterminal end.

The interconnecting region of the flap with the interior surface of thecap is preferably spaced radially inward from the sidewall 194 toaccommodate the cross-sectional thickness of the shoulder 120 extendingfrom the bottle. Thus, as illustrated in FIG. 6, the interconnectingregion of the flap with the cap interior surface is spaced approximately0.110 inches from the inner surface of the cap sidewall and the terminaland of the flap in an un-deflected state is spaced a greater distancefrom the cap sidewall inner surface. By way of example only, theterminal end 202 is spaced approximately 0.117 inches from the capsidewall inner surface, although these dimensions are meant to beexemplary only and not limiting. The general purpose of the inward bendand the tapering conformation of the flap is to provide centering of theseal flap/cap relative to the bottle opening as the cap is threaded ontothe bottle shoulder and the cap axially advances onto the shoulder.

The seal assembly of the present disclosure also includes a rigid pinchrib or shoulder 210 that is disposed radially inward of the flap.Particularly, the rib is spaced by radial gap 212 from the flap. Thepinch rib extends generally normally outward from the underside orinterior surface of the cap planar portion at a substantially reducedheight relative to the height of the flap. As shown in FIGS. 6 and 7,the rigid pinch rib has a height approximately one-half the height ofthe flap. The pinch rib is also illustrated as merging into a centraldepressed region on the cap although it will be appreciated that the ribcan also be formed as an annular projection extending from the undersideof the cap and over a limited radial extent if so desired. Preferably,the rigid material of the cap that forms the pinch rib can handlesubstantial compressive forces. Thus, as the cap is rotated onto thebottle, and significant radially inward forces are imposed on flap 200,an effective inner diameter seal is formed between the flap and thechamfer or tapered surface 214 of the bottle opening. As shown, thechamfer 214 is provided along the upper, inner face of the shoulder 104.That is, the chamfer 214 is preferably defined at the intersection orinterface of wall/shoulder 102 and the upper surface 124 of theshoulder. Further inward deflection of the flap, however, is precludedby the abutting engagement between the flap 200 and the rigid pinch rib210. Thus, as a radially outer face of the flap sealingly engages withthe bottle shoulder along chamfer 214, the opposite or inner face of theflap sealingly engages with the pinch rib 210.

This arrangement allows significant torque to be imposed on the cap tocreate the seal. The chamfer of the body shoulder serves as aself-centering or lead-in portion for the flap to assure proper locationof the cap on the neck opening. Moreover, the pinch rib 210 serves as astop to limit the torque imposed on the flap.

Moreover, because a sufficient torque on the order of about 20 inchpounds can be imposed on the cap (as compared to a approximately 2-5inch pounds in the prior art), there is no need for a separate foilseal, no need for a gasket, and if desired, the structure can be made sothat the cap is never removed from the bottle. That is, it iscontemplated that the opening may be used only for filling the bottle,the cap then positioned in place, and an anti-taper member or ring to240 (shown in dotted line in FIG. 6) provided on the lowest extension ofthe sidewall 194 of the cap. The anti-tamper ring 240 is secured bycircumferentially spaced frangible portions 242. An undercut region 244snaps into place over a radial protrusion 246 extending from theshoulder, but if the cap is subsequently removed from the shoulder, thefrangible connections will break, and thus provide clear indication ofattempted removal of the cap, i.e., tampering.

Alternatively, the arrangements of FIGS. 3-7 can also be used in adispensing opening. For example, with additional reference to FIGS. 3-5,a pour opening and pour lip are provided in a hinged cap (see co-pendingPCT application Serial No. PCT/US09/057336, filed 17 Sep. 2009, thedisclosure of which is incorporated herein by reference). By moving thepouring edge outwardly to the surface that extends radially outward fromthe sidewall, the overall height of the bottle can be reduced, and thusless plastic required in the total bottle.

As generally illustrated in FIGS. 3 and 4, the cap 190 includes anopening 300 that is selectively closed by hinged lid 302, andparticularly a seal member 304 that extends outwardly from the lid 302for receipt in the opening 300. A removable or tear-away seal panel 310in the cap (of the type generally shown and described in the co-pendingPCT application identified above) is preferably integrally molded withthe cap. The panel 310 is segregated about a periphery by a frangible,thin walled portion 312 where the tear-away panel interconnects with theclosing surface 314 of the cap. A tab, such as ring tab 320, is securedto the tear-away panel 310, and once a consumer opens the lid 302 of thecap assembly, by rotating the lid about the hinge 322 to an openposition (FIG. 8), the tab 320 is exposed and the consumer can removethe tear-away panel 310 by rupturing along the frangible connection.Once the tear-away panel is removed, the opening 300 is formed in thecap assembly. Likewise, seal 304 extending from the underside of the lid302 is dimensioned for a sliding sealing fit as an original seal, andsubsequent re-sealing of the contents of the fluid container.Tamper-evident protection is also provided by way of the tear-away panel310, i.e., a consumer can readily recognize if the tear-away panel ismissing and whether the contents of the container have been possiblycompromised. Use of the tear-away panel which may be easily removed bypulling on the ring tab 320 and removing the panel 310 from theremainder of the cap assembly 190, advantageously eliminates the needfor a separate foil seal, gasket, or similar structure.

The price of each cap can be reduced by approximately fifty percent(50%) with the present cap, while still maintaining the ability toeffectively seal along the inside of the neck, providing fortamper-evident capability, and providing an effective seal that allowssubstantial torque to be imposed on the cap to create the seal.

The disclosure has been described with reference to the preferredembodiments. Obviously, modifications and alterations will occur toothers upon reading and understanding the preceding detaileddescription. It is intended that the exemplary embodiment be construedas including all such modifications and alterations insofar as they comewithin the scope of the appended claims or the equivalents thereof.

1. A cap for selectively sealing an opening formed in an associatedbottle that includes an external thread portion around the opening, thecap comprising: a generally planar surface dimensioned to overlie theassociated bottle opening; a sidewall extending from the planar surfaceincluding internal thread portions thereon dimensioned for cooperativethreaded engagement with the associated bottle thread portion; a lipextending from one of the planar surface and the sidewall and directedinwardly from the sidewall for receipt in the associated bottle opening;and a shoulder extending outwardly from the planar surface and spacedinwardly from the lip for engaging the seal lip as the cap is threadedon to the associated bottle.
 2. The cap of claim 1 wherein the lip has avariable thickness along a length thereof.
 3. The cap of claim 2 whereinthe lip has a thicker cross-sectional dimension adjacent aninterconnecting region with one of the planar surface and the sidewall.4. The cap of claim 1 wherein the lip has a thicker cross-sectionaldimension adjacent an interconnecting region with one of the generallyplanar surface and the sidewall.
 5. The cap of claim 1 wherein the capis formed of a rigid plastic such as HDPE.
 6. The cap of claim 1 whereinthe lip extends from the generally planar surface and is spaced radiallyinward from the sidewall.
 7. The cap of claim 6 wherein the shoulder isspaced radially inward of the lip.
 8. The cap of claim 7 wherein theshoulder extends outwardly from the generally planar surface a dimensionless than the lip extends outwardly from the generally planar surface.9. The cap of claim 1 wherein the shoulder extends outwardly from thegenerally planar surface a dimension less than the lip extends outwardlyfrom the generally planar surface.
 10. The cap of claim 1 wherein theshoulder is spaced radially inward of the lip.
 11. The cap of claim 1further comprising a stop surface on the cap that is located tooperatively engage a corresponding stop shoulder on the associatedbottle to limit forces imposed on the lip and shoulder.
 12. A moldedplastic cap for a fluid bottle having an opening, the molded plastic capcomprising: a generally planar member dimensioned for covering receiptover the bottle opening; a sidewall extending outwardly in a firstdirection from adjacent a perimeter of the generally planar member andsurrounding the opening; a contoured lip extending a first dimensionfrom an interior surface of the generally planar member and inwardlyfrom adjacent a perimeter thereof; and a shoulder extending a seconddimension from the interior surface of the generally planar member andspaced further inwardly from the perimeter than the lip for sealinglyengaging the lip to the associated bottle.
 13. The cap of claim 12wherein the lip has a reduced thickness at a distal end relative to aproximal end.
 14. The cap of claim 12 wherein the cap is formed of arigid HDPE material.
 15. The cap of claim 12 wherein the lip firstdimension is greater than the shoulder second dimension.
 16. The cap ofclaim 12 wherein the sidewall includes a thread portion along an innersurface thereof for cooperative threaded engagement with an externalthread portion around the opening of the associated bottle.
 17. The capof claim 12 further comprising a stop surface for limiting advancementof the cap onto the bottle over the opening.
 18. The cap of claim 12further comprising a pour opening in the generally planar member and aclosure lid hinged thereto.
 19. The cap of claim 18 wherein the pouropening includes a thin walled tamper evident member integrally moldedwith the generally planar member.